Translucent polycrystalline alumina ceramic
AssigneeGeneral Electric Company
InventorsKarthik Sivaraman, Shuyi Qin, Ming Gao
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Abstract
A polycrystalline body includes aluminum oxide, magnesium oxide, zirconium oxide, and lutetium oxide. The lutetium oxide is present in an amount of at least 10 ppm of the weight of the ceramic body, and the magnesium and zirconium oxides are present at a molar ratio of from 0.5:1 to 3:1.
Claims21
A polycrystalline body for a high pressure sodium lamp comprising aluminum oxide, magnesium oxide, zirconium oxide, and lutetium oxide and wherein the lutetium oxide is present in an amount of at least 10 ppm of the weight of the ceramic body, the magnesium and zirconium oxides are present at a molar ratio of from 0.5:1 to 3:1;
- and
- wherein the total transmission of light by the polycrystalline body is at least 98%.
A polycrystalline body for a high pressure sodium lamp comprising aluminum oxide, magnesium oxide, and lutetium oxide, the oxides being present in the following amounts, expressed in parts per million of the weight of the ceramic body as follows:
- 100-250 ppm magnesium oxide,
- 100-630 ppm zirconium oxide,
- 10 ppm-120 ppm lutetium oxide, and
- wherein the total transmission of light by the polycrystalline body is at least 98%.
Dependencies are inferred from the claim text.